25-05-2012

CB&I signs SGS for pre and post weld heat treatment services in Colombia

SGS has been contracted to perform pre- and post-weld heat treatment (PWHT) processes for the CB&I expansion project at the Refinería de Cartagena S.A. (REFICAR) refinery in Cartagena, Colombia.

SGS will provide PWHT services in compliance with manufacturing codes ASME VIII, ASME B31.3 and B31.1 for pipes ranging in diameter from one to twenty-four inches. Dated March 20, the agreement specifies a project execution period of fourteen months to begin on April 1 this year and proceed until June 2013.

CB&I has designed, engineered and constructed some of the world's largest energy infrastructure projects and provided engineering, procurement, construction (EPC) solutions and proven technologies. One of the world's most prominent providers of EPC and process technology licensing, CB&I continues to offer a comprehensive range of solutions to the energy and natural resource industries. In the Cartagena project, CB&I is solely responsible for the engineering, procurement and construction of a multi-process unit refinery to be built adjacent to the existing REFICAR refinery.

Expansion at Cartagena
The expansion of the REFICAR refinery in Cartagena is one of the largest industrial projects to be undertaken in Colombia. Its goals are to increase gasoline and diesel fuel production to 140,000 barrels per day for domestic consumption and export sales in conjunction with improving the quality of the fuels according to mandatory emissions protocols required to meet international environmental standards and to optimize financial and operational indicators.

For an efficient, environmentally-sound and profitable concern, the existing refinery will undergo modernization renovations enabling REFICAR to take full advantage of the new complex.

Benefits of Heat Treatments
PWHT by definition refers to heat treatments done before and after welding designed to improve the chemical and mechanical properties of weldment surfaces. Preheating and/or post-weld heating treatments may be required when welding base materials for construction components. These thermal applications prevent or eliminate irregularities to guarantee the integrity of the finished weld.

There are two main reasons for implementing preheating weld treatment. The first is to eliminate any moisture from the weld area. Drying the material's surface by heating it to a temperature just above the point at which water boils prohibits any contamination which might result in porosity or hydrogen cracking.

The second reason is to lower the thermal gradient. Welding processes require extremely high-temperature heat sources resulting in big differentials in temperature between the heat source itself and the base material to be welded causing expansion, contraction and stresses around the weld area. Preheating reduces this temperature differential, improving the micro-structure of the heat affected zone (HAZ), lowering residual thermal stress and preventing rapid cooling to avoid cracking due to weld hardening.

Like preheating, post weld heat treatments are used to reduce stress for the purpose of ruling out any internal or residual stresses caused by the welding process. These stresses must be excluded in order to bypass distortions through subsequent handling, to eliminate the risk of stress related corrosion and to improve the overall metallurgical structure of the material by removing diffusible hydrogen, tempering the metal and enhancing material strength and life expectancy.

Application of Heat Treatments
Heat treatment may be administered by electrical resistant heating coils or by induction. Heating elements of NI-Cr wire of suitable gauge and insulated with porcelain beads are wrapped around the weld portion and electrically heated.

This method locally heats a circumferential band which includes the entire weld and the surrounding area of the base metal. Heating elements are sufficiently wrapped with mineral wool to shield the heat at 75 mm on both sides of the weld. The heating band measures at a minimum width of three times the density of the area being joined or two inches (50 mm) on either side of the weld.

SGS Quality Assurance Promise
In those welding operations which warrant pre- and/or post-weld heat treatments, SGS ensures that these processes are correctly conducted in compliance with the relevant welding procedure specifications and code requirements. SGS PWHT services are essential in assuring contractors and operators high-quality, compliant components thereby prohibiting potentially exorbitant costs associated with substandard, non-regulatory products. SGS preventive services are sought by successful, professional construction contractors, business owners and facility operators around the globe.

SGS is honored to have been chosen to assist CB&I in this distinguished project of paramount proportion.